This invention relates to steam turbines and more particularly to the closing blade locking system for a circular array of side entry rotating blades. Side entry rotating blades as shown in U.S. Pat. No. 4,533,298 are installed on a rotor disc one at a time and have a pin which is inserted after the blade is installed in a slot in the disc. The next blade to be installed captures the pin to prevent it from coming free. However the last blade to be installed cannot receive the locking pin and some other arrangement must be utilized to lock the last blade or closing blade in the circular array.